Seal for high pressure short-arc lamps



United States Patent I 72] Inventors [54] SEAL FOR HIGH PRESSURE SHORT-ARC LAMPS 4 Claims, 1 Drawing Fig.

[50] Field ofSearch 174/5053. 50.57, 50.58. 50.61, 50.62, 50.63; 313/220. 331. 182 [56] References Cited UNITED STATES PATENTS 3,390,296 6/1958 Smith Primary Examiner- Raymond F. Hossfeld Anorneysl-larry M. Saragovitz, Edward .1. Kelly, Herbert Berl and Harold W. Hilton ABSTRACT: A high pressure are lamp including an envelope enclosing a pair of electrodes. A pair of end caps are provided with a cylindrical portion enclosing the ends of the envelope. An epoxy bond is placed between the envelope and caps for securing the caps to the envelope. A deformable seal member is positioned between the ends of the envelope and the caps to [52] U.S.Cl 313/182, 174/5053. 174/5061:313/220.313/33l [51] lnt.Cl. H0lj61/36 enhance sealing therebetween.

l 1 I L *2? ayzo 2 5 PATENTED 115029 I970 DORWIN L. KILBOURN TEDDY J. PEACHER RAYMOND F. ASKEW WILLIAM D. FOSTER,

W VVENTQR SEAL FOR HIGH PRESSURE SHORT-ARC LAMPS BACKGROUND OF THE INVENTION High pressure short-arc lamps currently used are made from quartz by skilled glass blowers. The wide range of tolerances and the uncertainty of reliable operation of such lamps has necessitated efforts toward developing lamps of simplified construction which will eliminate glassblowing and the tolerances associated with it. One of the newer approaches uses an epoxy bond to hold metal end caps to the ends of the quartz tubing. These types of seals may have trapped air bubbles and pipes which develop into escape tubes for the gas in the lamp when it is pressurized to or atmospheres.

SUMMARY OF THE INVENTION The present invention utilizes a deformable sealing means between the ends of a high pressure are lamp tube and a pair of end caps which are sealed to the tube with epoxy cement.

It is, therefore, an object of the present invention to provide a high pressure nonleaking arc lamp which may be manufactured without resort to glass blowing techniques.

It is another object of the present invention to provide such an arc lamp with a pair of end sealing members having deformable seal means disposed between the end caps and the envelope in a manner which will enhance the sealing relation therebetween.

These an other objects and advantages of the invention will be more readily apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The FIG. is an elevational view partially in section of an arc lamp utilizing the principles of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the FIG. an arc lamp 10 includes an envelope 12 having a pair of end caps 14 and 16 disposed at opposite ends thereof. The envelope may be of quartz, or ceramic material. The end caps include a base portion 18 and a cylindrical portion 20. A deformable or malleable seal means 22 is disposed intermediate the base portion 18 and ends 24 and 26 of the envelope 12. A pair of electrodes 27 and 28 are secured, respectively, to end caps 14 and 16. The end caps are secured around the ends of the tube by clamping or other means. Preferably an epoxy seal 30 is disposed intermediate the cylindrical portion of the end caps and the tube for securing the caps to the tube. A tube 32 is secured in one of the end caps in an opening provided therein for the pressurization of 5 the lamp.

To enhance the seal between the ends of the tube and the caps. the ends of the tube are grooved or roughened at 34 adjacent the surface of the caps where the tube ends seat. Also. the seating surface of the caps are grooved or roughened at 35 and the deformable washer, made of indium, lead, or the like. is seated between the ends of the tube and the seating surface of the caps. Sufficient compressive force is applied between quartz tube and end caps, after epoxy is applied therebetween, to deform the washer so as to fill the voids in the rough surfaces of the tube and caps.

The epoxy is then cured and the lamp filled with gas to the desired pressure and the tube 32v sealed to prevent gas escapage.

It is to be understood that the washer may be of alloys of soft metals and/or synthetic materials which will withstand the heat content of the lamp.

Obviously, many modifications of the present invention may be resorted to by those skilled in the art without departing from the spirit and scope of the appended claims.

We claim:

I. An arc lamp structure comprising:

a. an envelope enclosing a pair of electrodes, said envelope having grooves on the endsthereof; b. a pair of end caps respectively secured to opposite ends of said envelope, said caps having a cylindrical portion for enclosure of the ends of said envelope and an inner surface having grooves therein;

c. seal means including a metallic deformable member mounted between the ends of said envelope and said caps, said seal means being disposed between the grooved surfaces of said envelope and said end caps and extending into said grooves; and

d. adhesive means disposed between said envelope and said end caps for secured relation thereof.

2. The device as set forth in claim 1 wherein said deformable means is indium.

3. The device as set forth in claim 2 wherein said adhesive means is epoxy.

4. The device as set forth in claim 1 wherein said deforma- 45 ble means is lead. 

